In recent years, demand is increasing for fiber-reinforced resin materials called FRPs or the like since such are lightweight and have high mechanical strength.
The demand for the fiber-reinforced resin materials is particularly increasing in the automobile field, the shipping field, the aviation field, and the like.
As the fiber-reinforced resin material of this type, a sheet-like material including an unsaturated polyester resin and glass fibers is widely used.
In recent years, a resin composite in which a fiber-reinforced resin material and a resin expanded body have been integrally laminated has been utilized in various uses (refer to Patent Document 1 mentioned below).